Consumer unit and fusebox upgrades to BS 7671:2018 Amendment 2.

What's included

• Full replacement of the existing board with a metal-enclosed consumer unit compliant with BS 7671:2018 Amendment 2:2022
• Choice of dual-RCD split-load (economy) or all-RCBO (higher spec) configuration
• Type 2 SPD (surge-protection device) fitted as standard - mandatory under A2 on domestic supplies unless specifically risk-assessed out
• Main earthing and bonding upgraded to current requirements if the existing bonds are undersized (a common finding on pre-2000 installations)
• Full test and inspection: Ze, PSCC, RCD ramp and trip tests, insulation resistance on every circuit, polarity and continuity
• Electrical Installation Certificate (EIC) issued on completion
• Building Regulations compliance certificate self-certified under a Competent Person Scheme and posted to you within a fortnight
• DNO (UK Power Networks) called to isolate and re-seal the supply at meter tails

Which boards get replaced

These are the boards that flag on nearly every EICR I run in Canterbury:

• Wylex plug-in fuseboards (wooden-backed). No RCD protection, rewireable ceramic fuses, exposed live tails inside the fuse-carriers when withdrawn. Category C1 on EICR - code for "danger present, requires immediate remedial work". Common in unmodernised Wincheap and St Dunstan's terraces.
• Metal-clad rewireable-fuse boards. No MCB protection, no RCD, no way to add either. Common in mid-C20th Hales Place and Thanington semis.
• Early MCB boards (Wylex Standard, MEM Memera). MCB protection but no RCD. Category C2 on EICR - "potentially dangerous". Requires either full replacement or an RCD retrofit that in practice never quite works out cheaper than a new board.
• Plastic-enclosed 17th-Edition boards. Since Amendment 3 in 2015, new domestic boards inside habitable spaces must be metal-enclosed. A plastic-enclosed board in a hallway cupboard is treated as end-of-life on renewal. C3 on EICR - "improvement recommended".
• Single-RCD split-load 17th-Edition boards installed before 2022. Now non-compliant on new installs under A2, though existing installations are not automatically failed. Usually replaced with an all-RCBO board when a rewire touches the sub-main.

What A2 changed

Amendment 2:2022 to BS 7671:2018 took effect for new installations from 27 September 2022. The main changes that affect a consumer unit swap:

• SPD by default. Type 2 surge-protection is required on domestic installs unless the risk assessment (BS 7671 Section 443) specifically excludes it. In practice that means the SPD goes in every new board.
• AFDD requirement extended. Arc-fault detection devices are required on socket circuits in HMOs, care homes and other higher-risk premises, and recommended on all others. On a standard domestic upgrade an AFDD-per-circuit spec is optional but adds meaningful protection against arc-fault fires.
• All-RCBO now the preferred spec. A2 explicitly notes that all-RCBO configurations should be considered for domestic installations to limit the number of circuits affected by a single fault. Dual-RCD split-load remains compliant but is treated as the economy option.

Canterbury-specific notes

Listed properties inside the walls. The board itself is not a listed feature, but the run of any new circuit into a listed elevation or the surface conduit route back from an updated meter position needs a scope conversation first. If the sub-main from meter to board is being re-run and the route crosses a listed corridor or a lath-and-plaster wall, that is a Listed Building Consent conversation with Canterbury City Council.

DNO isolation. UK Power Networks are usually 24–48 hours out for a scheduled cut of the meter tails to re-seal. I book the DNO slot on your behalf and quote the job for the day the DNO can come. Emergency isolation is available where the existing board is actively dangerous.

Metering. If you have a Smart Meter fitted after 2018, the isolation is by the supplier not the DNO. That is a different call and a different timeline.

Frequently asked

Do I need a new consumer unit if my current one still works?

Not automatically. BS 7671 does not require retroactive replacement - an existing installation is not made non-compliant by the publication of a new Amendment. But if an EICR codes the board C1 (danger) or C2 (potentially dangerous) it needs to be replaced to keep the certificate satisfactory. In practice, any pre-2000 board and most 2000–2015 single-RCD boards will C2 or C3 today.

How long does a consumer unit swap take?

Half a day of on-site work on a standard 8-way to 12-way board once the DNO has cut the tails. The DNO isolation slot is the pacing item - usually 24 to 48 hours notice at UK Power Networks. Full test, inspection and certificate on the same day.

Will you upgrade my main earthing at the same time?

If the existing main earth conductor is undersized against the current PSCC or the main bonds to gas and water are 6mm² or less, yes - the earthing upgrade is quoted alongside the board because a new board on undersized earthing is not compliant and would flag C2 at the very next EICR.

Pricing

Consumer unit upgrades on a Canterbury property start from £600. All-RCBO spec, AFDD retrofit or larger boards (10+ circuits) push higher. Includes the SPD, the DNO isolation coordination, testing, EIC and the Building Regulations compliance certificate. Fixed price quoted in advance after property details and scope. No day-rate creep, no surprise extras.